And even the concept of one virtue being “better” than another
REQUIRES
an objective standard.
“Or for that matter, why is altruism “better” than selfishness?”
Because, when we are altruistic, we reflect the love that God has for us on to others, and, in doing so, prove ourselves better than the animals. Selfishness is simply following our baser instincts, and leaves us in the same moral condition as a pig or an ape.